1. Field of the Invention
This invention relates generally to a test sample color comparison device for use in biochemical examinations (blood sugar, urine sugar, urobilin and other such examinations), and more particularly to a wheel of such a device to which a color sample is adapted to be bonded so that the color sample on the wheel can be compared with a test paper impregnated, for example, with blood as the wheel is rotated relative to the test paper. The color sample which best matches the color of the test paper provides an indication of a characteristic of the impregnating material, e.g., blood.
2. Discussion of Related Art
Japanese Patent Application No. 282780/87 and U.S. patent application Ser. No. 268,561 filed Nov. 8, 1988 disclose a test sample color comparison device which is compact in size and enables an easy and rapid measurement of body chemistry such as the amount of blood sugar, urine sugar or the like.
FIG. 4 is an exploded perspective view of the test sample color comparison device disclosed in the above applications which comprises a casing unit 1 housing a CPU (central processing unit) and other electronic circuits, a wheel 6 which is fitted on the casing unit 1 and has a color sample section 3 for holding a color sample (which may be in the form of a sticker) at an upper surface thereof and an uneven patterned code section (uneven patterned code plate) 6a at the underside thereof, and a cover unit 4 fitted on the casing unit 1. The casing unit 1 has an insertion section 11 for removably receiving a color test portion of a test stick, and a protruding display section 12 for displaying the results of the color comparison. The wheel 6 is rotatably fitted on the protruding display section 12 of the casing unit 1, and the wheel 6 is so arranged that the comparison color sample section 3 having different staged reference color shades 1, 2, 3, 4, 5, 6 7 and 8 arranged in a circular array on the upper surface thereof can be viewed through a display window 41 formed through the cover unit 4. A plurality of converter switches K.sub.1, K.sub.2, K.sub.3 and K.sub.4 are mounted on the casing unit 1 independently of one another and disposed in corresponding relation to the wheel 6 (the uneven patterned code plate 6a), so that these switches can convert the results of a visual comparison between the color comparison sample section 3 and the color test portion to electrical signals. The uneven patterned code plate 6a integrally mounted on the underside of the wheel 6 has an uneven pattern defined by thickened portions and thinned portions, and this uneven pattern operates or turn on or off the converter switches K.sub.1, K.sub.2, K.sub.3 and K.sub.4 in accordance with the rotation of the wheel 6.
In the above color comparison device, the color test portion of the test stick is inserted into the insertion section 11, and the wheel 6 is rotated to visually compare the color of the test portion with the reference color shades on the color sample section 3. Then, when one of these reference color shades coincides with the color test portion, the wheel 6 is stopped in that position, and a start switch is turned on. As a result, the position of the wheel 6 and therefore the color are identified in accordance with the states (ON or OFF) of the converter switches K.sub.1, K.sub.2, K.sub.3 and K.sub.4, so that corresponding measurement data are read out through the eelectronic circuits and are displaced on the display section 12.
In the above test sample color comparison device, the color test portion of the test stick is disposed over the color sample section 3 of the wheel 6. Therefore, as measurements are conducted over and over again, blood or urine impregnated in the test portion is transferred to the color sample section 3 to stain it. Therefore, it is necessary to replace the color sample section with a new one once in a while. Further, the test sticks are sold in the form that a predetermined number of (for example, 50, 100 or 300) tests sticks are contained in a bottle, a can or the like. These bottles or cans of test sticks have different properties, and therefore different color sample labels are attached to the different bottles or cans, respectively. Therefore, each time a different bottle or can of test sticks is used, the color sample section 3 is exchanged. However, since the color sample section 3 is typically in the form of a sticker which is adhesively bonded to a groove portion 6d formed between inner and outer circumferential protrusions 6b and 6c formed on the upper surface of the wheel 6, the color sample sticker 3, once bonded to the groove portion 6d, cannot easily be peeled therefrom. Thus, the problem is that the exchange of color sample stickers takes considerable time and labor.